Processes for various conversions of low molecular weight olefins are well known in the prior art. Representative of such general conversion processes are U.S. Pat. Nos.: 3,140,249; 3,140,251; 3,140,253; 3,140,322; and 2,972,643.
The conversion of paraffins, olefins and/or naphthenes to aromatics using a ZSM-5 catalyst is disclosed in U.S. Pat. No. 3,756,942. The conversion of olefins to aromatics by use of ZSM-5 and ZSM-8 is disclosed in U.S. Pat. No. 3,760,024. The prior art relating to olefin conversion over ZSM-type catalysts also includes numerous process related patents including: U.S. Pat. No. 3,775,501 (co-feed air with olefins over ZSM-5); U.S. Pat. No. 3,827,968 (ZSM-5 in a two step process); U.S. Pat. No. 3,960,978 (ion-exchange and/or steamed ZSM-5 or ZSM-11); U.S. Pat. No. 4,021,502 (olefin conversion using ZSM-5, ZSM-12, ZSM-18, chabazite and beta zeolite under controlled process conditions); U.S. Pat. No. 4,150,062 (use of co-fed water with olefins over ZSM-5); U.S. Pat. No. 4,227,992 (ethylene/propylene conversion over ZSM-12 employing controlled process conditions).
The above processes employ the aluminosilicates generally known as "ZSM-type" aluminosilicates. (The term "ZSM-type" is generally employed in the literature to denominate the aluminosilicates assigned a "ZSM-n" name where "n" is an integer.) Accordingly, such processes do not relate to a process or processes not employing aluminosilicate molecular sieves.
The use of certain novel non-zeolitic molecular sieves as "polymerization" catalysts to produce high boiling polymerization products is disclosed in U.S. Pat. Nos. 4,440,871 (SAPOs), 4,500,651 (TAPOs), 4,567,029 (MeAPOs and MAPOs) and 4,544,143 (FAPOs). The interconversion of C.sub.2, C.sub.3 and C.sub.4 olefins using certain non-zeolitic molecular sieves is not disclosed in the aforementioned applications. U.S. Pat. No. 4,310,440, discloses that aluminophosphates (AlPO.sub.4) may be employed as polymerization catalysts.
A process for the oligomerization olefins to hydrocarbon fuels is disclosed in U.S. Pat. No. 4,528,414, commonly assigned. The instant invention is to be distinguished from the aforementioned oligomerization process by the selection of specific non-zeolitic molecular sieves for the instant olefin interconversion whereby less than 20 mole percent of the C.sub.2 to C.sub.4 olefins are converted to products containing greater than five carbons.